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Finishing Finishing Methods WOODFINISHINGSurface PreparationThe first step to a good finish is to make sure the surface the finish will be appliedto is free of all defects such as dents, gouges, scratches and milling marks. Mostfinishes bring out the natural grain and beauty of the wood. Unfortunately, theymay also magnify any defects that may have gone unnoticed. What appears tobe a minor defect on raw wood will stand out like a sore thumb when a stain orfinish is applied.Common Sense.Surface preparation should begin before the project is assembled. A fair amountof common sense should be used during construction. For example: any surfacethat cant be easily reached after assembly should be sanded before assembly.In general attention to detail such as tight joint lines and excess glue squeeze outshould be addressed during construction. Excess stain will accumulate betweenpoorly fitted joints and will appear as unsightly dark lines when the finish hasbeen applied. The glue squeeze out should be left to dry and then removed byusing a scraper. During construction I am constantly asking myself, "How will thisaffect the surface when I apply a stain or finish"? Ask yourself this while youwork.Mill MarksIf you wish to build a quality piece of furniture, I recommend buying good qualitylumber, free of knots, sap, blemishes etc. If you do so, about the only defect youwill have to deal with on the board will be mill marks. When boards are runthrough a planer, the rotating planer knives take shallow bites out of the wood.Mill marks appear as a series of repeating raised bumps that run across the grainof the board. If the knives are very dull, the marks really stand out, but more oftenthey are less pronounced, in some cases invisible to the naked eye. Its importantto note that mill marks are present on every board that has been run through aplaner, regardless of quality or source.Sometimes mill marks are very hard to see. If you dont detect and remove them,they will really stand out once a stain or finish has been applied. The best way tosight mill marks or any other minor flaws or defects is to use reflected light.Position a lamp above the work surface at about a 30 degree angle to thesurface. You will be surprised when the marks you could not see before now looklike mountain peaks and valleys. Overall, the best way to remove mill marks andother minor defects like small surface scratches is by firstname.lastname@example.org Wisdom Management Services (M) Sdn. Bhd. 1
Finishing Finishing MethodsSandingChoosing The Right PaperThere are several types of sandpaper, some are designed for sanding finisheslike lacquer and varnish while others are best for sanding raw wood. GarnetPaper is an orange colored sandpaper that is made of a natural abrasive. It isexcellent for sanding raw wood. Another type of paper that is favored by furnitureand cabinet makers for sanding raw wood is Aluminum Oxide paper(sometimes known as production paper). This is the standard brownish coloredpaper found in most hardware and paint stores. Aluminum Oxide is a man madeabrasive and will last a little longer than Garnet paper. Either of the two willproduce excellent results. The types of paper you want to stay away from forsanding raw wood are the Silicon Carbide (Wet or Dry) paper which is black incolor, and the light gray colored papers which are lubricated and used to sandlacquers and other topcoats.Grits.Sandpaper is graded by using a number system. The finer the paper, the higherthe number. Garnet and Alum. Oxide paper range in grit sizes from 36 (VeryCorse) to 240 (Fine).Choosing A SanderOver the past few years a variety of sanders have been introduced onto thewoodworking market. Some work very well, while others, not so well. The threemost common sanders used for surface prep are a belt sander, orbital sander(pad sander) and the most recent random orbital sander. Each sander producesa distinct surface finish. A belt sander is best used when a lot of material has tobe removed from the surface. For example when glued up boards have to beleveled. It is a dangerous tool, make one mistake and you may wind up ruiningthe workpiece. Even though a belt sander removes stock quickly, I dont think itsworth the risk. The belt sander leaves straight lined scratch pattern.While orbital sanders do not remove stock like belt sanders, some of theheavier models like the Porter Cable Model 330 Speed Bloc will do a great job ofremoving scratches and milling marks when a piece of 80 grit sandpaper ismounted to it. These sanders leave small orbital scratch patterns that are nearlyinvisible to the naked eye. When using an orbital sander, dont press down toohard on the worksurface. Let the weight of the machine do the job. Although youcan initially sand across grain make sure you take your last passes with the grainto avoid leaving scratch marks on the stock. The random orbital sander is themachine I most often use. Because it creates an orbital as well as revolvingmotion, it removes stock much quicker than a pad sander and at the same timeleaves a scratch pattern that is almost swirl free, even when sanding email@example.com Wisdom Management Services (M) Sdn. Bhd. 2
Finishing Finishing Methodsgrain. To properly use this sander, start it while it is on the wood. If you wait untilit is running at full speed before you set it on the work, it may gouge out thesurface.Sanding SequenceMany woodworkers believe that if you sand the work to a super fine grit, you willachieve a better finish. This is not true. The only purpose for sanding is toremove mill marks, tool marks, other defects and to smooth the surface. Whensanding, sandpaper leaves small grooves relative to the grit size of the paper youare using. By sanding with progressively finer grits you are making these groovessmaller. Once the grooves are small enough so they cant be seen with thenaked eye, you do not need to go any further. While it is not necessary toprogressively sand using every available grit, you should not skip too many gritsizes. Use a grit that is just small enough to remove the grooves left by theprevious paper. I usually use 100 grit to remove milling marks and any othersurface defects, then move to 180 to refine the grooves and finish up with 240grit. If mill marks are very pronounced, I will start with 80 grit, then use 120 andfinish with 220. Sanding up to 220 or 240 on most woods will make the groovessmall enough so they are naked to the invisible eye. However, there are somespecies of wood that may require sanding to a finer grit before the grooves arenot visible.SAFETY NOTE! PLEASE WEAR A RESPIRATOR OR FILTER MASK WHILE PERFORMING ANY SANDING OPERATION.Sanding should proceed as follows:1. Remove mill marks and other surface defects using 80 or 100 grit paper.2. Once mill marks are removed, move up to a medium grit paper (120 or 180grit). This will refine the scratch pattern. To see if you have removed all of thedeeper grooves left by the previous grit paper, first blow off the sawdust thenmount a lamp above the worksurface (at about a 30 degree angle). The reflectinglight will show any deeper grooves that may have been left. Continue to sanduntil all the deeper grooves are firstname.lastname@example.org Wisdom Management Services (M) Sdn. Bhd. 3
Finishing Finishing Methods3. Continue on using 220 or 240 grit. On most woods the scratches left by 220 or240 grit paper will be small enough as not to be seen by the naked eye. If youcan still see scratches under reflected light, move up to a finer grit usually 280grit.Sanding MethodRegardless of the type of sanding machine you use, there are some basic rulesto follow. Many texts and articles tell the reader never to sand against the grain.This is not always true. When you first start to sand using coarse paper it may benecessary to remove a lot of material because you have to remove mill marksand level the surface. Initially sanding against the grain will remove stock muchquicker. Once mill marks are removed and the surface has been leveled, finishup by sanding with the grain before moving up to a finer grit. Also there are somecases where you are forced to sand against the grain. One such case is at a jointline where two pieces of wood meet at an angle. In this case it is also o.k. tosand against the two pieces, just make sure you finish by sanding with the grainup to the joint line.Removing excess glue squeeze out.As mentioned previously, you should use a good amount of common senseduring the construction process. Removing excess glue squeeze out is a perfectexample of this. Many woodworkers have a number of theories about how andwhen to remove glue squeeze out. One theory I do not agree with is to removethe glue while it is still wet by using a damp cloth. By doing this, you are forcingthe glue down into the pores. Furthermore, if you use a damp cloth, you arethinning the glue out thus it will penetrate even deeper into the pores of thewood. This method also makes it difficult to determine if all of the glue has beenremoved. If the glue has not been totally removed in some areas, it will act as asealer and prevent a stain or finish from penetrating into the wood.When the stain or finish is applied, the area in question will appear light andblotchy. Another method that works much better is to let the glue set up beforeremoving it. As white or yellow glue dries, it first starts to skin over and form ablister. If you dont wait long enough before removing the glue, the skin will breakopen and deposit wet glue onto the work surface. If you wait about 45 minutes to1 hour, the glue should be dry enough to remove easily with a paint or gluescraper. There is a way to test the glue in order to determine if it has setup to email@example.com Wisdom Management Services (M) Sdn. Bhd. 4
Finishing Finishing Methodspoint where it should be removed. Take a pin and prick one of the globs of glue,if the blister breaks and fresh glue comes out it is not yet ready to be removed.Wait a while longer. If the glue is left to dry hard it could be difficult to remove,however not impossible. I would still recommend using this method over themethod of removing the glue with a damp cloth while still wet. A good paintscraper is the best tool for glue removal. The scraper should have a solid bladeand sharp edge. It should also have a large heavy handle.Some Final Tips!Removing Sawdust. Use a tack cloth to remove sawdust from the worksurface.Lightly wipe the surface, dont rub hard or press down or the resin in the tackcloth will be deposited on the worksurface and may contaminate it. Start thefinishing process immediately after the surface has been prepared.Humidity in a shop can start to raise the grain and if you handle the workpiecetoo much after it has been sanded, the natural oils in your hands may alsocontaminate the workpiece. Hinges, pulls and other hardware. Drill allmounting holes for hinges, pulls and other hardware before you sand and thenmount the hardware to test the fit and location. Once satisfied remove allhardware before you start to sand. Do not remount the hardware until the wholefinishing process is firstname.lastname@example.org Wisdom Management Services (M) Sdn. Bhd. 5
Finishing Finishing Methods Furniture repairAs an introduction, a few words about the author of this column. While I now dofurniture repair and refinishing only as a hobby and for a "sideline" income, Iworked at it full-time for a number of years, both in furniture stores that had theirown shops, as well as establishments whose sole business was to repair andrefinish furniture. I make no claim to being an authority on furniture periods orstyles, but I do know a little about furniture work, which I’ll try to pass on in thesecolumns. I have learned over the years there’s a lot of mystery associated withfurniture repair and refinishing (probably promoted by those in the business!) thatneedn’t be. Hopefully, some of the "tips and tricks" you read here will bolster yourenthusiasm for what can be a very rewarding and productive hobby. If you haveany specific questions, address them to me at the Enterprise, with a self-addressed, stamped envelope, and I will answer. If your question has enoughgeneral appeal, I’ll use it in this column.Unless your home has recently been entirely refurnished, you’ve probably got atleast one piece that has a "watermark" that ugly white blotch left from waterstanding on the surface too long before it was wiped up. It may be just a fewdots, or a ring left by a glass or planter. If the mark is white there’s good news(Black watermarks are another problem we’ll deal with later).To fix 1 piece of furniture, or 15, you’ll have to spend about $10.00. You’ll need0000 (called four oh) steel wool; Turtle Wax polish and Scratch remover for cars(This product has a very fine abrasive mixed in with the wax which will let you geta super shine.); some clean rags, and some oil. Whatever oil you cook with willwork, Puritan, Wesson, etc. makes no difference.Pour about 1 teaspoon of oil directly on the watermark. It should fadeconsiderably and may disappear. Don’t be deceived, it’s still there. Rub the markgently with the steel wool, moving with the grain of the wood, not across. After aminute of this procedure, wipe it clean to see how much of the mark you haveremoved. Repeat this procedure, using as little pressure as necessary to scratchthe surface, until the mark is gone. Apply the Turtle Wax according to thedirections on the can. This will remove the abrasion marks left by the steel woolYou’ll have to do the entire surface in order to get a uniform sheen, so be readyfor some work when you start to remove that mark on the dining room table!On a large piece, there’s a lot of "elbow grease" involved, but not a lot ofexpense. There are other products that will work as well as Turtle Wax, but that’sthe one I use. Just be sure it’s not a polishing or rubbing compound. Thoseproducts have an abrasive grit that’s much too rough for furniture finish work.A little background: 99% of factory made furniture is finished with lacquer, whichwill absorb standing water, and in some cases of constant high humidity, directlyfrom the air! The white marks are caused by water that has become trapped email@example.com Wisdom Management Services (M) Sdn. Bhd. 6
Finishing Finishing Methodsthe finish. The procedure described above simply removes the very top layer offinish, getting rid of the water(mark).Furniture stripperThe primary requirement for furniture work is patience. Nowhere is thischaracteristic needed more than in stripping furniture. Let’s see if we can makethis messy task any easier.First, what do you need? Specific items will vary from piece to piece, but thefollowing list should get you through most jobs. You’ll need stripper, of course.What kind? You basically have two options, and then two choices within eachoption. Here are the options. If you’re really keen on the environment, you’ll wanta water-base stripper. They work fine, and as the label suggests, you can washthe residue off with water. The downside is that using a water based strippermeans you must. sand the piece completely before you do anything else. Asolvent based stripper doesn’t raise the grain of the wood, but you have to bemore careful with it. Sanding is kept to a minimum. Whether you choose water orsolvent base, your next choice is going to be liquid or semi-paste. Liquid usuallystrips faster, but the semi-paste is excellent for adhering to vertical surfaces andcarved material to remove the old finish from all the cracks and crevices.Other items you’ll need include a flexible blade drywall knife, 3", with a dull edgeand slightly rounded corners. No, you can’t buy it that way, except for the 3" andflexible part. Dull the edge and round the corners slightly with a file. This will helpprevent gouging the wood when you scrape off the old finish. Steel wool, both XXand 00 grades, to help remove what the putty knife doesn’t get, as well as towork on carvings and legs. Industrial grade rubber gloves. The kind sold forwashing dishes won’t last - don’t bother. When I worked where cotton rags wereplentiful and cheap, that’s what I used. Now I use paper towels, and buy them inthe 12 pack when they’re on special. If you’re using a solvent base stripper, you’llalso need some lacquer thinner - a quart will be plenty. Get a natural bristlebrush, not synthetic, preferably the cheapest one you can find, 2" wide, forapplying the stripper. Lots of old newspapers to cover the floor under and aroundthe area you’re working in and a quart of paint thinner. If you buy a length of 1/4"or 5/16" dowel rod and cut it into 5-6" lengths and then run both ends through apencil sharpener, you’ll have some great tools for digging in cracks and crevicesthat won’t chew up the wood. Some disposable foil pans for pouring the stripperinto and catching the mess as it comes off will also be handy.Now what? A well-ventilated, well lit and well ventilated area to work in; oldclothes that you can afford to throw away if necessary; and patience. Everystripper I’ve seen says put it on (in such-and-such manner) and let it stand for atleast 15 minutes...and nobody does. Read the directions and follow them. Thezaini@selectvest.com Wisdom Management Services (M) Sdn. Bhd. 7
Finishing Finishing Methodspeople that made the stuff know more about it than you do. They put directionson the can so you’ll get good results and use their product again, instead ofsomething else. If you don’t have a watch, borrow one. Time yourself whenapplying stripper. It will save you a lot of work and frustration in the future.By the way, the paint thinner is used to clean the piece before you do anythingelse. Stripper won’t cut through grease, oil, or wax. Paint thinner will removethem all. The lacquer thinner is used as a final wash (with solvent strippers) afteryou’ve finished stripping. It will remove the last traces of stripper (so it won’tattack the new finish) and will neutralize any left in the cracks and firstname.lastname@example.org Wisdom Management Services (M) Sdn. Bhd. 8